[Velomobile] Velomobile design

[Gavin.Walker at csiro.au]

Hi Everyone,
  I joined this list years ago hoping to get inspired into building a velomobile.  Young children, landscaping and an unenthusiastic wife have gotten in the way.  So I still have a trike aero shell hanging in my garage but no trike or progress.  I am not sure if I will be able to contribute this list but I'll throw some requirements for the sort of velo I'd like.

1. Cost: Under $5k.  Rotovelo comes close but has other down sides. I will have to buy a second car soon which will be about $10k, travel 5k km a year and cost 4k a year in parts and depreciation.  However the benefits are well known and shareable.  I currently have 12k km up on my bike over 12 years however a good velomobile might see 5-10k km a year.  Considering a suspended trike costs about $5k this price maybe too optimistic.

2. Speed: 32km/h. Current commute is 35minutes at 22km/h on the bike.  Speed increases versatility.  Lifting the average speed to 32km/h (20mph) would cut commute to 25minutes.  Interestingly if my commute has 30% uphill at 20km/h, 30% downhill at 60km/h and 40% flat at 40km/h the average speed is about 32km/h.  Wind kill downhill and flat speed, weight kills uphill speed and weight kills uphill speed.  Uphill contributes more to longer trip times than fast downhill removes.

3. Power assist.  Australia may have a limit of 200W but I tell you an unfit person riding an assisted bike is difficult to keep up with.  The biggest contributor to the weight of vehicle is the rider not the vehicle.  If a good cyclist puts out 300W and weigh 100kg including the bike, then adding 200W and 30kg is equivalent to the original cyclist with a total weight of just 80kg.  Power assist is also essential for cargo capacity as the weight kills performance so much.  Trike builders tend to by HPV purists and electric assist is not a common option.  Batteries are really heavy anymore so speed governs range more than battery weight.

4. Cargo capacity: 1+1.  The ability to cram in a passenger or cargo makes the velo more than just a toy.  This is the biggest problem with the trike plus fairing option.  There are very few 1+1 trikes primarily because of the lack of power assist I suspect.  To be useful the cargo capacity must be inside the weather shell.

5. Weather protection.  Both rider and cargo need protection.  Lack of weather protection will halve the number of days it can be used and renders it not much better than a trike.

6. Suspension: Canberra bike paths are full of tree roots and ramps.

7. Safety.  There is not a big motorcycle culture in Australia.  People I know who rode motor cycles generally stopped after their first accident.  Canberra has largely segregated cycle ways making velo usage possible.  I would not be riding a velo on the open road.  It is no better than motorcycle and lacks the power to get out of the way of blind motorists.  First assumption on a bike is the motorist is dumb.  If the velo is hooking downhill at 60km/h I would also want protection in case control is lost.  Rolling, sliding or hitting a tree.  Generally I'm thinking of seat belts, full face helmets and impact absorbing shell (such as a honeycomb shell).


Gavin Walker
Canberra, Australia